Sustaining the Environment

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A person stands in a multimedia installation about forest fires during the Green Nation Fest environmental show in Rio de Janeiro on May 31, 2012. Rio is hosting the United Nations Conference on Sustainable Development. Victor R. Caivano/AP

Cyclists carry their bicycles as they participate in World Car Free Day in Brasilia on Sept. 22, 2011. Participants switched from cars to bicycles in an effort to raise environmental awareness and promote bicycles as a cleaner and more sustainable mode of transport. Ueslei Marcelino/Reuters

Abraham Pardee saws a piece of metal during demonstrations to show how natural resources are reused to make sustainable products at the Ornamental Metal Museum in Memphis, Tenn., May 26, 2012. Kyle Kurlick/The Commercial Appeal/AP

In this May 22, 2012 photo, a road crosses through an agricultural area of a forest in San Francisco de Macoris, Dominican Republic. Conservationists are blending sustainable agriculture with preservation on former pasture land at the edge of a cloud forest to protect a songbird called Bicknell's thrush. Ricardo Arduengo/AP

A parking station for the Autolib' electric car-share scheme is seen on a street in Paris on Dec. 2, 2011. Paris launched an electric car-sharing program to cut air and noise pollution on the city's medieval cobblestone streets and beyond. Christophe Ena/AP

Recycling bins are seen at the Center for Alternative Technology in Machynlleth, Wales, March 25, 2010. Stefan Wermuth/Reuters

Trash cans are tagged in different colors for waste segregation inside the 30-story T30 Hotel built by the Broad Group in Yueyang, Hunan province on April 24, 2012. China Daily/Reuters

A worker is dwarfed by the structure of 'Supertrees' in Singapore on June 29, 2011. These 'Supertrees' are vertical gardens, embedded with environmentally sustainable functions. Wong Maye-E/AP

When the coffee plantation owner working with Asomobi, a woman-led coffee cooperative, decided to plant trees next to his grove in El Carmen, Costa Rica, the coffee plants thrived, wildlife returned to the area and a once dry spring began producing water again, May 2007. The area buffers La Amistad National Park. Andy Nelson/ The Christian Science Monitor/File

A worker climbs the ladder to a windmill at Horns Rev 2, the world's largest wind farm, 19 miles off the west coast of Denmark near Esbjerg in this Sept. 15, 2009 file photo. Now a world leader in wind power, Denmark gets a quarter of its electricity from wind and aims to increase that share to 50 percent by 2020. Bob Strong/Reuters/File

A cow stands near windmills at an eolic farm in Cerro de Hula, 15 miles south of Tegucigalpa on April 21, 2012. The Cerro de Hula is Central America's largest wind farm with a capacity of 102 MW, according to local media. Jorge Cabrera/Reuters

This April 20, 2012, photo shows free reusable metal water bottles to be distributed to any student who signs a pledge to not use bottled water for personal use and to use tap water whenever possible in order to receive a free reusable metal bottle at a table in Hubbard Park in Iowa City. Cliff Jette/Cedar Rapids Gazette/AP

Steam rises from the chimneys of a thermal power plant, with the air temperature at about -15 degrees Celsius (5 degrees Fahrenheit) in Moscow, Dec. 2, 2010. Mikhail Voskresensky/Reuters